Why Don’t Big Dogs Live as Long as Small Dogs?

Large animals tend to live longer (sometimes much more so) than smaller ones*. A cat is going to live longer than a rat, you’re going to live longer than a cat and a Galapagos tortoise is going to live longer than you. The world’s smallest mammal, the bumblebee bat, is thought to live 5 to 10 years, while the largest, the blue whale, lives for 80 to 90. Scientists think that this happens because of the way differently-sized animals use energy. Big animals’ cells are slower and more efficient, so their parts wear out slower and last longer.

Forget about all the other animals and focus on just one species, though, and you see this trend reverse. Within a species, larger size seems to carry a longevity cost. Scientists have seen this is in mice, horses, and even humans**. The phenomenon is well known to dog lovers: Dogs from bigger breeds don’t live as long as smaller ones. The small breeds have an average life expectancy of 12 to 14 years; for larger breeds, it's 8 to 10; and for the so-called “giant breeds,” lifespan is 5 to 8 years.

This strange flip in the relationship between size and lifespan isn’t completely understood, and many, if not all, of the factors at play are probably species-specific. This is certainly the case for dogs, and scientists think that the reasons big breeds die young have to do with the way humans have bred them and the way they grow.

Larger dogs grow very big very fast. Take a one-year-old Great Dane, for example. It’s huge. From birth to their first birthday, they increase 100-fold in weight. In that same time frame, wolves increase 60-fold, poodles 20-fold and humans only threefold. Research in the last decade has suggested that larger individual animals die younger because this sort of accelerated growth comes with increased free-radical activity.

A new study published last month focused only on dogs and likewise concludes that big dogs die young because they age quickly. The European researchers looked at veterinary data for 74 breeds and more than 50,000 individual dogs, including when and how they died, and found that “large dogs age at an accelerated pace, suggesting that their adult life unwinds in fast motion.”

Faster aging isn’t the only explanation, though. Larger dogs are more prone to health issues like developmental disorders, musculoskeletal and gastrointestinal diseases, and tumors—all of which are also linked to their accelerated growth and appear to be the nasty side effects of selective breeding for large size over a short (relative to the millennia other animals have had to evolve by natural selection) period of time.

* There are some notable exceptions, of course, like the relatively small African grey parrot, which can live 50 to 60 years.

** Tom Samaras has been studying links between human height and other characteristics for decades. After looking at height and age of death for people in a number of historical samples, he found that shorter stature is strongly linked to longer life. Among 3200 deceased pro baseball players, for example, he worked out that every cm of height a player had over the average shortened his life by .35 years.

It took a backpacking trip to Thailand and a bit of serendipity for Kanchan Singh to realize her life goal of saving cats while serving lattes. “I met these two guys on the road [in 2014], and we became friends,” Singh tells Mental Floss about Crumbs & Whiskers, the bicoastal cat cafe she founded in Washington, D.C. in 2015 which, in addition to selling coffee and snacks, fosters adoptable felines from shelters. “They soon noticed that I was feeding every stray dog and cat in sight," and quickly picked up on the fact that their traveling companion was crazy about all things furry and fluffy.

On Singh’s final day in Thailand, which happened to be her birthday, her friends surprised her with a celebratory trip to a cat cafe in the city of Chiang Mai. “I remember walking in there being like, ‘This is the coolest, most amazing, weirdest thing I’ve ever done,'” Singh recalls. “I just connected with it so much on a spiritual level.”

Singh informed her friends that she planned to return to the U.S., quit her corporate consulting job, and open up her own cat cafe in the nation’s capital. They thought she was joking. But three years and two storefronts later, the joke is on everyone except for Singh—and the kitties she and her team have helped to rescue.

Crumbs & Whiskers—which, in addition to its flagship D.C. location, also has a Los Angeles outpost—keeps a running count of the cats they've saved from risk of euthanasia and those who have been adopted. At press time, those numbers were 776 and 388, respectively, between the brand’s two locations.

Prices and services vary between establishments, but customers can typically expect to shell out anywhere from $6.50 to $35 to enjoy coffee time with cats (food and drinks are prepared off-site for health and safety reasons), activities like cat yoga sessions, or, in D.C., an entire day of coworking with—you guessed it—cats. Patrons can also participate in the occasional promotion or campaign, ranging from Black Friday fundraisers for shelter kitties to writing an ex-flame's name inside a litter box around Valentine's Day (where the cats will then do their business).

Cat cafes have existed in Asia for nearly 20 years, with the world’s first known one, Cat Flower Garden, opening in Taipei, Taiwan in 1998. The trend gained traction in Japan during the mid 2000s, and quickly spread across Asia. But when Singh visited Chiang Mai, the cat cafe craze—while alive and thriving in Thailand—had not yet hit the U.S. "Why does Thailand get this, but not the U.S.?" Singh remembers thinking.

Once she arrived back home in D.C., Singh set her sights on founding the nation’s first official cat cafe, launching a successful Kickstarter campaign that helped her secure a two-story space in the city’s Georgetown neighborhood. Ultimately, though, she was beat to the punch by the Cat Town Cafe in Oakland, California, which opened to the public in 2014, followed shortly after by establishments like New York City’s Meow Parlour.

LA customers at cat cafe Crumbs & Whiskers

Courtesy of Crumbs & Whiskers

Still, Crumbs & Whiskers—which officially launched in D.C. in the summer of 2015—was among the nation’s first wave of businesses (and the District's first) to offer customers the chance to enjoy feline companionship with a side of java, along with the opportunity to maybe even save a tiny life. Ultimately, the altruistic concept proved to be so successful that Singh, sensing a market for a similar storefront in Los Angeles, opened up a second location there in the fall of 2016. "I always felt like what L.A. is, culturally, just fits with the type of person that would go to a cat café," she says.

Someday, Singh hopes to bring Crumbs & Whiskers to Chicago and New York, and “for cat cafes as a concept, as an industry, to grow,” she says. “I think that it would be great for this to be the future of adoptions and animal rescues.” Until then, you can learn more about Crumbs & Whiskers (and the animals they rescue) by stopping by if you're in D.C. and LA, or by visiting their website.

We’re all familiar with the most dramatic metamorphosizers of the animal kingdom: butterflies. They go from a tiny egg to an awkward wiggling caterpillar to mysterious pupa to a delicate, colorful winged creature. However, there are many other animals besides butterflies that undergo dramatic transformations from youth to adult. Here are 15 of the most epic metamorphoses seen in nature.

1. LADYBUGS (COCCINELLIDAE)

What’s black, white, and red all over? Mandy ladybugs are—but only in their final stage of life. Turns out these little beetles undergo one of the most epic metamorphoses in the animal kingdom: For most species, after adult female ladybugs mate, they lay a clutch of tiny yellow eggs right in the middle an aphid colony, usually on the underside of a leaf. Eggs hatch in a week, revealing spiky black worm-like larvae that readily gobble up the aphids around them. When a larva is fully grown, it changes into a blob-like yellow pupa. Finally, the black, white and red (or sometimes yellow or orange) insect appears.

2. MAYFLY (EPHEMEROPTERA)

Mayflies, the less-elegant cousins of dragonflies and damselflies, have one of the most unique metamorphoses of all insects. Most insects’ life stages move from egg to nymph to pupa to adult, but mayflies do not have a pupa stage. Instead, it is the only type of insect to undergo a subimago stage, meaning it’s almost an adult in the sense it grows wings … but cannot fly long distances and isn’t yet sexually mature. The mayfly’s final life stage, the fully flighted and sexually mature imago or adult, is extremely short, lasting just a few hours to a few days.

4. NUDIBRANCH (NUDIBRANCHIA)

While adult nudibranchs are essentially colorful and ornate blobs of the sea, they don’t start out that way. In fact, after hatching, nudibranch larvae are tiny, plain-looking and have small snail-like shells. Over the course of two months they morph from this plain stage into adults, along the way getting larger and more colorful, losing their shells, and growing gills and feelers, called rhinophores.

5. CROWN OF THORNS STARFISH (ACANTHASTER PLANCI)

Another sea creature that looks completely different as an adult than a juvenile is the crown of thorns starfish. When looking at an adult, it’s easy to see where this creature gets its name: It’s completely covered with dangerous-looking sharp spikes. But after hatching, it looks like not much more than a translucent, floating blob. Over time it grows arms, and later, spikes, then fixes itself to rocks where it feeds on coral.

6. IMMORTAL JELLYFISH (TURRITOPSIS DOHRNII)

The secret to a long and prosperous life, it turns out, is to be a jellyfish. The aptly named immortal jellyfish begins life as an egg, like all other jellies. It then enters the free-swimming larva stage, then settles down into a polyp on the ocean floor, and then finally morphs into a sexually mature jellyfish. Unlike most other jellies, an immortal jellyfish is capable of reverting back into the polyp stage at any time it faces environmental stress, attacks by predators, sickness or old age—essentially being reborn as a young jelly.

7. FLATFISH (PLEURONECTIFORMES)

Think of Pablo Picasso’s most asymmetrically painted human face, stick it onto a fish, and there you have a flatfish. These fish, which include flounder and sole among other species, begin life inside tiny eggs that float up to the surface of the sea. For a few weeks, a larval flatfish swims upright and looks just like a typical baby fish. But after a few weeks its skull bones shift and one eye migrates to the opposite side of its face, forcing the now-lopsided fish to swim sideways. Eventually, when its facial features all move to one side of its face, it changes color and moves to live on the bottom of the sea, its blind side facing down.

8. EASTERN HELLBENDER (CRYPTOBRANCHUS ALLEGANIENSIS)

Also called the snot otter and devil dog, the eastern hellbender is a giant type of salamander not exactly known for being beautiful in its adult form. Slippery, wrinkly and the color of mud, they’re right at home at the bottom of rivers, where they can live up to 50 years. Like all salamanders, hellbenders begin as eggs. From their eggs they hatch, coming into the world small and adorable. As time passes, they grow larger and less cute.

9. CHALAZODES BUBBLE NEST FROG (RAORCHESTES CHALAZODES)

Don’t let this lime-green frog’s bright and cheery looks fool you: It lives in only one tiny area in India and is critically endangered, threatened most by an ever-shrinking habitat. These creatures were once believed to lay eggs that developed into tadpoles on pond surfaces like many other frogs. But in 2014, it was discovered that they had a different reproductive strategy: The frogs crawl into a living bamboo shoot that has a hole in it (probably created by insects or rodents) and lay their eggs there. The creatures skip the tadpole stage entirely, hatching as froglets. Because they don't have a tadpole stage, the species doesn't require water to lay its eggs.

10. MIMIC POISON DART FROG (RANITOMEYA IMITATOR)

Covered in bright hues spotted, striped, banded, and blotched with contrasting black, the poison dart frog is one of the most striking-looking of all amphibians. Yet they don’t start out that way. After hatching, young mimic poison dart frogs are looked after by their mother, who lays a clutch of unfertilized feeder eggs to provide them with some nourishment (and, at least for some species of poison frog, toxicity). Tadpoles are brown and black, growing more colorful with age until they reach their fantastic adult form.

11. KEA (NESTOR NOTABILIS)

The kea is a large, vulnerable species of parrot native to New Zealand, with green and blue feathers on its back and brown and orange feathers on its underside. While adult keas appear majestic and beautiful, they don’t start out that way. Baby keas retain an alien-like, sparse white hairdo for several months after hatching. Keas are considered a very intelligent species, observed working together and using tools.

12. LAYSAN ALBATROSS (PHOEBASTRIA IMMUTABILIS)

Laysan albatrosses are another species of bird where the babies are very little like their parents. But unlike baby keas, baby Laysan albatrosses hatch as adorable fuzzy gray blobs. As they grow older, the babies slowly grow adult feathers and lose their baby feathers. This leaves them with unique hairdos that sometimes make them look like human celebrities. Ringo Starr, anyone?

13. FLAMINGO (PHOENICOPTERUS)

Left: Getty Images // Right: iStock

Unlike keas and albatrosses, baby flamingoes look a lot like their parents, except they’re missing something: color. Flamingo chicks hatch with gray and/or white feathers, over time taking on the same pink hue as their parents, which becomes more intense over time. Why? Well, you are what you eat, and flamingoes eat shrimp and algae rich in carotenoids, the same pigments that cause shrimp to turn pink when cooked.

14. VIRGINIA OPOSSUM (DIDELPHIS VIRGINIANA)

Virginia opossums are scavengers, eating carrion and rotting vegetation, and that helps keep the environment clean. Virginia opossums are native to North America, where they’re the continent’s only living marsupials. This opossums have pouches for carrying their babies, just like kangaroos. Also like kangaroos they give birth to large numbers of navy-bean size babies, which grow inside their pouches. When they’re born, they look more like pink jellybeans than animals. Over the course of three to five months, they mature, growing fur, sharp teeth and long tails.

15. GIANT PANDA (AILUROPODA MELANOLEUCA)

Getty Images

Giant pandas are called giant pandas for a reason: They’re enormous in size, weighing up to 250 pounds. But these bamboo-munching bears don’t start out that way. When born, giant panda cubs weigh just 90 to 130 grams (about as much as a small apple). Besides being way smaller in size, baby pandas are also quite sparsely furred—and so they look very different than what they will as fuzzy black-and-white adults.